viii Johanna G. Hodges
and move them into the soil profile, making them more available to other
plants. A further mechanism is that of modifications in the rhizosphere caused
by the roots of plants grown in intercropping, something which can improve
the availability of mineral components. Some species have the capacity to
release or cause the activation of enzymes and secretion carboxylates by the
roots such malonates, citrates and malates, which improve the solubility of
nutrients in the rhizosphere and increase their bioavailability for plants. The
impact of intercropping on the availability and uptake of components by plants
depends on the selection of species for cropping, soil properties and course
conditions. In this chapter the possibility is discussed of using intercropping,
especially strip intercropping, in an effective and economically efficient crop
biofortification.
Chapter 2 – In semiarid and subhumid regions diagnosis of soil fertility
acquires a relevant role, as yields are limited by the lack of water. Changes in
management practices such as fertilization, rotations and no tillage alter the
dynamic cycling of organic matter in soil and influence nutrient availability.
There is no information available about of Southwest of Buenos Aires in
Argentina on the dynamics of P in relation to productivity. In this chapter are
evaluated edaphic characteristics, like texture and pH, the effect of tillage,
crop rotations, fertilizer application about dynamic of P forms in soil. The
texture determines P reserves and balance of its forms in soils. Available P,
predominantly inorganic, is linked to the fine fraction of the soil. The level Po
is greater in the coarse fraction of soil with a high content of fine fractions. No
tillage produces a stratification forms of P, modifies the proportion of organic
forms at different depths and changes the relationship between the organic
forms and available, and produces more export P cycling and maintaining the
occluded fraction available. The soil organic matter and its fractions are
indicators of changes that are caused by the crop system, which may be
considered to evaluate differences relative to the nutrients that cycle. Not only
is the amount of your contribution but specifically in relation to the forms of P,
may show changes in their structure that will change the way the nutrient
interacts with the soil matrix. On the other hand it could be detected, that the
inclusion of pasture rotation maintains lower levels of phosphorus available to
plants, but this sequence maintains high levels of P moderately labile, which
would be likely to be available during the cycle culture. Southwest of Buenos
Aires in Argentina there is a sensible equilibrium between the availability of
N, P and soil water that entails taking into account the three factors
simultaneously when designing strategies fertilization. To fertilize P deficient
soils is achieved more efficient water use, offsetting the adverse effects of a